Hydraulic tool



M. KLINGLER 3,070,143

HYDRAULIC TOOL Dec. 25, 1962 3 Sheets-Sheet 1 Filed Oct. 13, 1959 1952 M. L. KLINGLER 3,070,143

7 HYDRAULIC TOOL File d Oct. 15, 1959 s Sheets-Sheet 2 INVENTOR. NfiRTlN KLINGLER M. L. KLINGLER HYDRAULIC TOOL Dec. 25, 1962 3 Sheets-Sheet 5 Filed Oct. 15. 1959 INVENTOR. MAR-rm L. KMMGLER 3,079,143 HYQRAULEQ TOOL Martin L. Klingler, Hershey, Pa., assignor t AMP Incorporated, Harrisburg, Pa. Filed Oct. 13, 1959, Ser. No. 846,099 6 Claims. (Cl. 153-4) This invention relates to fluid-operated tools for compressing or crimping electrical connectors onto wires or performing similar operations.

In the crimping of electrical connectors onto the ends of wires, it is important that the connector be crimped or compressed to the requisite degree for best results. If a connector is only partially crimped, or is not crimped to the extent for which it was designed, the resulting connection may appear to be satisfactory although in fact the connection might have latent defects which would give rise to inferior tensile strength or inferior electrical conducting ability. Since it is impossible to determine from visual inspection whether or not a crimped connection has been properly made, it is desirable to employ tooling which is substantially fool-proof and with which it is imposible, or at least extremely diflicult, to form anything bnt a properly crimped connection.

An object of the present invention is to provide a fluid-operated crimping tool for electrical connectors or the like which ensures proper and complete crimping of the connector ferrule. A further object is to provide a fluid-operated crimping tool having trigger means or the like for initiating a crimping cycle, and having means to ensure complete cycling of the tool after the trigger has been depressed, regardless of the length of time during which the trigger is held in a depressed condition. A further object is to provide a fluid-operated crimping tool which will completely cycle during a crimping operation only if the pressure of the fluid is above some predetermined minimum level. A further object is to provide a fluid operated crimping tool having a valve means remote from the tool for controlling its operation and including a remote control on the tool for the valves.

These and other objects are achieved in a preferred embodiment comprising a single stroke fluid motor for moving a pair of crimping dies relatively towards each other, a source of compressed fluid for driving the fluid motor, and a control valve system for regulating the supply of pressurized fluid. The control valve system comprises a passageway extending from the source of pressurized fluid to the fluid motor system and having an inlet valve in the passageway which is normally maintained in the closed condition by the pressure of the motive fluid itself. This inlet valve is opened by means of a slidable free piston having a first face which is subjected to the pressure of the motive fluid and a restricted passageway extending from the one face to the opposite or second face so that the opposite face is also subjected to the pressure of the motive fluid. An exhaust valve is provided for rapidly exhausting the pressurized fluid from the opposite or second face of the free piston to cause movement of the piston towards the inlet valve, the restricted passageway through the piston being too small to permit instantaneous equalization of the pressure on the two sides of the piston. This piston is adapted to engage and open the inlet valve to initiate a crimping cycle for the tool. Upon movement of the free piston, it is engaged by a spring biased latch and locked against return movement so that motive fluid is supplied through the inlet valve to the fluid motor system until this latch is disengaged. Such disengagement is achieved by means of a relief valve which is so adjusted that it opens only when a predetermined minimum pressure is achieved in the fluid motor system of the crimping tool. Upon open- 3,0?fl,li3 Patented Dec. 25, 1962 ing of this relief valve, a second piston is moved into engagement with the latch means and disengages it from the free piston to permit return of this latter piston to its initial position.

The use of a crimping device in accordance with the invention certifies the finished crimp in two respects as follows: Since the piston which opens the inlet valve is retained in the opened position by the spring-biased latch, it is not essential that the exhaust valve, the opening of which initiates the crimping cycle, be kept open during the entire cycle. If the operator opens the exhaust valve only for a brief instant, the free piston will open the inlet valve and the free piston will thereafter be kept in engagement with the inlet valve until the cycle is completed. Furthermore, the cycle can not be completed unless the relief valve is opened and this event will occur only if the required pressure exists in the motive fluid. If the pressure does not exist, the crimping dies will be held in their partially closed position until the system is exhausted by a diflerent method. Of course, the mere fact that the tool does not completely cycle itself in indicative of some malfunction or possibly of insufficient pressure in the motive fluid.

In the drawing:

FIGURE 1 is a sectional view of a crimping. tool and fluid supply system which embodies the invention; and

FIGURES 2 and 3 are semi-diagrammatic views of the control valve system showing the positions of the parts at two different stages of the cycle.

The preferred embodiment comprises a hand tool generally indicated at 2 and including a C-shaped head portion 4 having a fixed die 6 and a movable die 8 which is secured to the end of a piston rod 10. The piston 12 to which piston rod 10 is secured is biased downwardly as viewed in the drawing by means of a spring 14 but is driven upwardly upon the admission of motive fluid into the cylinder 16 from a hose 24 through a coupling 22 which is threaded into the cylinder 16. A handle portion 18 attached to cylinder 16 provides a hand grip and a trigger mechanism for initiating the crimping cycle as described more fully below.

The opposite end of hose 24 is threaded by means of a coupling 26 into the end of a cylinder 28 which constitutes the high pressure hydraulic side of a pressure intensifier. Normally hydraulic fluid such as oil will be contained within the bore 30 of the cylinder so that upon movement of a plunger 32 into the cylinder, the tool piston 12 will be driven upwardly. The low pressure side of the intensifier comprises a cylinder 34 having a piston 36 therein which is normally biased against the back wall 38 of a cylinder by means of a spring 40. This spring bears against an annular diaphragm 44 which is clamped at its inner and outer edges at 46, 48 between cylinder 34 and the enlarged base 29 of cylinder 23. This diaphragm and the recessed face 31 of base 29 define reservoir 42 for the hydraulic fluid, the reservoir having communication with the open axial bore 30 of cylinder 28 by means of a passageway 50. It will be noted that this passageway is so located that it is uncovered only when piston rod or plunger 32 is in its fully retracted position and that upon initial movement of piston rod 32 and piston 36 the port or passageway is covered. Thus, the extremely high pressures which are generated in the hydraulic side of the intensifier are not transmitted to reservoir 42.

The control system for regulating the admission of compressed air into cylinder 34 comprises a valve body 54 secured to the external surface of back wall 38. This valve body provides an inlet port 56 which receives the threaded end of a fitting 58 on the end of a hose 60 which extends to a source of compressed air. A passageae'zonee way 62 extends from this inlet into a chamber 64 which constitutes one portion of a bore extending through the valve body and which is plugged at its open end as shown at as. An inlet valve 78 in chambered has an O-ring d8 which seats against a shoulder in the bore. Adjacent this shoulder is a restricted diameter bore section '72 which, in turn, opens into an intermediate chamber 74. A stem '76 on valve 70 having a conical end 78 extends through bore section 72 into chamber 74. A passageway 88 leads from chamber 74 through the valve body and communicates with an opening in the back wall 38 of cylinder 34 to permit admission of pressurized air into this cylinder. Valve 74 is normally maintained in the closed condition (i.e. O-ring 68 is normally seated against the shoulder) as shown in FIGURE 2 by virtue of the pressure of the compressed air from the line on its underside 82..

Chamber 74 opens into a somewhat larger chamber 84 in which is slidably mounted a valve spool or free piston 86 having a central portion which is of substantially the same diameter as chamber 84 and having a first side 88 which is exposed to the line pressure by means {of passageways 89, 91, the passageway 89 communicating with inlet port 56; A reduced diameter extension 9%) of the free piston extends axially and slidably into a bushing 92 in upper section of chamber 84, and a washer 94 and snap ring 96 in this chamber prevent upward moveinent ofthie piston 86 beyond the position shown in the FIGURE 2-. Extending from reduced diameter section is a projection 98 which is shouldered near its end to form and end portion 100. It will be noted that the end portions 98, 100 of this free piston extend beyond the valve body and that the shoulder 99 between the portions 98 and 0 is above the surface of the valve body in FIGURE 2.

The opposite side 104 of piston 86 has a reduced diameter extension 102 which projects into chamber 74. A restricted. passageway 106 extends through the central portion of the free piston 86 and between the faces thereof so that the pressure of the line acts against the lower iace 104 of this piston as well as the upper face 88. As is apparent from the drawing the area of face 104 is greater than the area of face 88 and the free piston is, therefore, biased upwardly when the pressure on the two sides is the same. A port 108 opening into chamber 84 communicates with an outlet port 110 which receives a threaded fitting on the end of a hose 112 (FIGURE 1). The opposite end of this hose has a fitting 1141 which is threaded into the handle 18 of the tool itself. This tool handle has a passageway 116 which is enlarged at its lower end 118 for the accommodation of a ball check valve 124). A rod 122 in this passageway has its upper end in engagement with a pivotally mounted trigger 126 as shown at 124 so that upon clockwise movement of the trigger, as viewed in the drawing, the rod 122 is pushed downwardly to unseat the ball check valve 120 and exhaust air from the underside of piston 86 through a port 121 in the tool handle. The valve 12% thus constitutes a bleeder valve for bleeding air from the underside of piston 86. When the underside of this piston is exhausted, the free piston is moved downwardly since the restricted passageway N6 is not sufficientiy large to equalize the pressure between the two faces of the piston.

As the piston moves downwardly, the face of the reduced diameter portion 102 engages the cone-shaped end 78 --of valve 7% and this cone-shaped end enters and closes the axial exhaust bore lill in the piston itself. Substantially simultaneously, valve 78 is pushed downwardly as viewed in the drawing thus permitting passage of compressed air from the source through passageway 72, into chamber 74', and thence through passageway 80 into cylinder 34 as shown in FIGURE 3. Piston 36 and plunger .32 are thus driven towards cylinder 28 and the hydraulic ;fluid in the bore of this cylinder is compressed to drive the crimping dies relatively towards each other.

Upon movement of free piston 86 downwardly, it is locked in its downward position by means of an L-shaped latch having arms 128, 134 which is pivoted at 130 between a pair of upstanding ears extending from the valve body 54-. A spring 129 normally biases arm 128 downwardly as viewed in FIGURE 2 so that the end of arm 134 is pressed against the surface of extension 98. Upon downward movement of the free piston, the end of this arm moves over the shoulder 99 and the free piston is latched against return movement. In this manner, inlet valve 76 is held open until the latch is disengaged. Such disengagement is achieved by means of a plunger 144) having a bifurcated end 136 which is engageable with the end of latch arm L28. This plunger extends through an adjusting nut 138 and into a chamber in the valve body and has on its end a piston 144. A spring normally biases this piston downwardly so that the conical end 146 on the face of this piston is normally seated in the outlet port of a passage 149. Passage 149 communicates with a passage 148 which in turn communicates with the interior of cylinder 34 through back wall 38. Spring 1145 and nut 138 are so adjusted that valve 146 is opened when the pressure within the cylinder reaches the desired level. Upon opening of this valve, piston 144 moves upwardly thereby swinging the latch in a counterclockwise direction around its pivot 136 and permitting upward travel of piston 86.

Advantageously, a safety valve is provided which comprises a piston and plunger 15%] spring-biased upwardly in a chamber 151. If, for any reason, excessive pressures are developed in the system and the valve 146 does not open, plunger 15-h would be urged downwardly by the excessive pressure in the system and uncover an exhaust port 151.

To summarize, the operator places the uncrimped terminal and wire between the dies and squeezes the trigger. Air is exhausted from the underside of free piston 86 causing downward movement thereof to open valve '70. At the same time the central exhaust bore in this free piston is closed by conical valve 78. Compressed air then flows through passageway 80 into cylinder 34 thereby to drive plunger 32 into bore 30 and move the dies relatively towards each other. During this portion of the cycle, the free piston is held in its downward position as viewed in FIGURE 2 against the end 78 of valve 70 by latch arm 134. Thus, even if the operator squeezes the trigger only instantaneously, the inlet valve is held open. When the system reaches equilibrium, which is to say when the pressure is uniform throughout, the relief valve 146 is opened and plunger Mil moves upwardly thus disengaging latch arm 134 from the free piston, which moves upwardly under the influence of the air pressure on its face Hi4 and the face of projection 102. Valve 7% also moves upwardly by virtue of the line pressure on its face 82 and the inlet valve is thereby closed. Air is exhausted from the main cylinder by means of the axial bore TM in the free piston which is open to the atmosphere after the free piston moves upwardly.

The overall advantage which accrues from the instant invention is that incomplete or improper crimping of the terminal is virtually impossible. If, for any reason the air pressure of the compressed air source to which hose 68 extends should fall below the required level, the crimp can not be completed since relief valve 146 will not open unless this predetermined pressure exists in passageway 149 and, therefore, in cylinder 34. Thus, if the line pressure should drop to a low level momentarily by reason of a malfunctioning compressor or because of the use of a large amount of compressed air by another device, the dies in the crimping tool will remain partially closed until full line pressure is regained and the dies can be completely closed. If full line pressure is not regained, the dies will remain partially closed as a signal to the operator that the air pressure is inadequate and a proper crimp can not be made. Under these circumstances, the arm 12% can be digitally lifted to open the dies.

The instant invention also eliminates virtually all dependence upon the operator for proper tool operation. If the operator merely squeezes the trigger momentarily, the tool will automatically cycle itself as explained above. If the operator holds the trigger for several seconds, the dies will close and remain closed until the trigger is released at which time they will open. In the latter case, when the dies complete the crimp, the relief valve is opened and latch arm 134 is disengaged from the free piston, but the free piston itself is unbalanced and held against cone 78 by virtue of the effect of the line pressure against face 88. When the trigger is released, the pres sure on face 104 and on the face of projection 102 is sulficient to drive the piston upwardly.

It will be noted that there is virtually no loss of compressed air when the trigger is squeezed excepting, of course, the air in hose 112, and the small amount of air which flows through restricted passageway 106 during downward movement of the free piston. The opening of the inlet valve 70, the closure of bore 1M by cone 78, and the closure of exhaust port 108, however, take place substantially simultaneously so that there is no direct flow of air from the compressed air source through the exhaust ports before they are closed.

In FIGURES 1-3, valve body 54 is represented in two dimensions in the interest of facile disclosure. The actual construction of the preferred embodiment is shown in FIGURE 1. Sealing rings on the several pistons and cylinders of the disclosed embodiment have not been specifically identified in the description since their functions are believed to be obvious from the foregoing description and the drawing.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective against the prior art.

I claim:

1. In a fluid operated crimping tool comprising a hydraulically actuated piston-cylinder, said piston having a crimping die thereon, a single stroke pneumatic-hydraulic intensifier for supplying hydraulic fluid to said pistoncylinder comprising, a compressed air source, a passageway extending from said compressed air source to said intensifier, inlet valve means and exhaust valve means in said passageway normally maintained in closed and open position respectively by the pressure of said compressed air source, bleeder valve means for relieving the closing pressure on said inlet valve means and said exhaust valve means whereby, said inlet valve is opened and said exhaust valve is closed upon opening of said bleeder valve means, latch means engageable with said inlet valve means to hold said inlet valve means in open position, and fluid pressure actuated means for disengaging said latch means from said inlet valve means upon attainment of a predetermined pressure.

2. Apparatus as set forth in claim 1 wherein said fluid pressure actuated means for disengaging said latch means comprises a pressure relief valve operable upon attainment of a predetermined pressure.

3. Apparatus as set forth in claim 1 wherein said bleeder valve means in located on said hydraulically actuated piston-cylinder.

4. In a fluid operated crimping tool comprising a hydraulically actuated piston-cylinder, said piston having a crimping die thereon, a single stroke hydraulic-pneumatic intensifier for supplying fluid under pressure to said piston-cylinder, and means for supplying compressed air to said intensifier comprising, a compressed air source, a passageway extending from said source to said intensifier, an inlet valve in said passageway normally maintained in the closed position by compressed air from said source, bleeder valve means for relieving the closing pressure on said inlet valve whereby, said inlet valve is opened upon opening of said bleeder valve, automatic latch means engageable with said inlet valve upon opening thereof to maintain said inlet valve in open condition regardless of the condition of said bleeder valve, and pressure sensitive means for disengaging said latch means from said inlet valve upon attainment of a predetermined pressure in said intensifier thereby to ensure completion of a crimping operation by said piston.

5. In a fluid operated crimping tool comprising a hydraulically actuated piston-cylinder, said piston having a crimping die thereon, a single stroke pneumatic-hydraulic intensifier for supplying hydraulic fluid to said pistoncylinder and means for supply compressed air to said intensifier comprising, a compressed air source, a passageway extending from said compressed air source to said intensifier, inlet valve means in said passageway normally maintained in closed condition by the pressure of said compressed air source, bleeder valve means for relieving the closing pressure on said inlet valve means whereby, said inlet valve is opened upon opening of said bleeder valve, spring biased latch means engageable with portions of said inlet valve when said inlet valve is opened to hold said inlet valve in open position, a plunger engageable with said latch means to release said valve opening means, a piston on the end of said plunger, and a pressure relief valve for admitting compressed air from said intensifier to said pressure relief valve whereby, said pressure relief valve is opened and said piston and plunger are advanced to disengage said latch means from said inlet valve when the predetermined pressure of said relief valve is reached.

6. A crimping tool comprising, a movable crimping die, means including a source of pressurized fluid and a pressure intensifier piston and cylinder for moving said die upon admission of fluid into said pressure intensifier cylinder, a passageway extending from said source to said intensifier cylinder, an inlet valve in said passageway normally maintained in closed condition by said pressurized fluid, inlet valve opening means normally biased by said pressurized fluid out of engagement with said valve and movable into engagement with said valve to open said valve upon bleeding pressurized fluid therefrom, a spring biased latch engagcable with said inlet valve opening means upon movement thereof to maintain said valve opening means in engagement with said inlet valve thereby to maintain said valve in open condition, fluid actuated means engageable with said latch to disengage said latch from said inlet valve opening means, a passageway connecting said intensifier cylinder with said fluid actuated means, and a relief valve in said passageway whereby, compressed fluid from said intensifier cylinder is effective to actuate said means upon attainment of the opening pressure of said relief valve thereby to disengage said latch from said inlet valve opening means and to permit closure of said valve.

References Cited in the file of this patent UNITED STATES PATENTS 2,310,625 Fischer Feb. 9, 1943 2,426,492 Dupre Aug. 26, 1947 2,600,860 Dupre June 17, 1952 2,649,076 Dupre Aug. 18, 1953 2,684,003 Klingler July 20, 1954 2,710,019 Reasoner et al. Iune 7, 1955 37,135 Demler June 3, 1958 2,387,916 Freedom May 26, 19 9 ,703 Fischer et al Aug. 4, 1959 2,962,074 Dupre et al Nov. 29, 1960 

